The outside of Solfaterra's cone, near Puzzoli, Kingdom of Naples, c 1760.

Hand-coloured etching by Peter Fabris (active 1768-1779). Illustrated plate from William Hamilton's studies of Italian volcanoes, 'Campi Phlegraei' (published in Naples, 1776). The image shows the outside of Solfaterra, and with the road from Naples to Puzzoli (now known as Pozzuoli) that was cut into the mountain. According to Suetonius, Caligula took a large quantity of stone from this section of the mountain to pave the roads of Italy. Hamilton's book is a seminal work on the nature and effects of volcanic activity.